const querystring = require('querystring');

let obj = querystring.parse('rsv_n=2&rsv_sug=21&rsv_sug1=16&rsv_sug7=100');

console.log(obj);
/**
{ 'rsv_n': '2',
  rsv_sug: '21',
  rsv_sug1: '16',
  rsv_sug7: '100' }
 */